1. Field of the Invention
The present invention relates to a technical field in which solid pulverized and/or lumpy objects formed in a deposited layer are pushed and moved in predetermined quantities, and more particularly to an apparatus for pushing such pulverized and/or lumpy objects.
2. Description of the Related Art
This type of apparatus is used extensively in a field in which solid pulverized and/or lumpy objects are handled, and is also used in, among others, a heating furnace apparatus such as the one shown in the appended drawing, FIG. 6.
In FIG. 6, a substantially horizontal hearth 51 having the shape of an annular plate is rotatively driven around a vertical axis 52. An outer cylinder 53 and an inner cylinder 54 which constitute parts of a furnace body are disposed above the hearth 51, and the inner cylinder 54 is connected to a furnace cover 55. An annular space 56 is formed by the hearth 51, the outer cylinder 53, and the inner cylinder 54. The pulverized and/or lumpy objects to be calcinated are supplied from the outside into the annular space 56 through supply pipes 58 provided in such a manner as to penetrate an upper wall 57 for connecting the outer cylinder 53 and the inner cylinder 54, and are stored therein, thereby forming a deposited layer 59 in the annular space 56.
A burner 60 and an air supply pipe 61 are provided through the furnace cover 55, and the deposited layer 59 is subjected to preheating on a combustion space 62 side by means of heat from combustion gases in the combustion space 62.
Rod-like pushers 63 extending toward the center are provided through the outer cylinder 53 at a plurality of circumferential positions. Each of the pushers 63 is coupled to a rod of a cylinder unit 64 provided on the outer side, and is reciprocated in the longitudinal direction of the pusher 63 while being guided by a guide portion 53A of the outer cylinder 53, and pushes the preheated pulverized and/or lumpy objects toward a drop port 51A in the hearth 51 on each occasion of its reciprocating motion. The dropped pulverized and/or lumpy objects form a deposited layer again in a vertical furnace 65 and are allowed to mature in an upper portion of the deposited layer, are then allowed to drop to a lower portion of the vertical furnace 65 while being cooled by air which is supplied from the lower portion of the vertical furnace 65 and rises through the deposited layer, and are taken out as products. The air which has undergone a temperature rise and has assumed a high temperature, after having cooled the pulverized and/or lumpy objects matured in the vertical furnace 65 and having risen through the deposited layer, contributes to the combustion in the combustion chamber 62. The exhaust gases after combustion are passed through the deposited layer 59 on the hearth 51, and are discharged from exhaust pipes 66.
With the above-described apparatus shown in FIG. 6, the pushers 62 provided at a plurality of circumferential positions above the hearth 51 are generally reciprocated with their operating timings staggered, and cause the pulverized and/or lumpy objects to drop in predetermined quantities uniformly in the circumferential direction in conjunction with the rotation of the hearth 51. As for the above-described pushers, there are cases where a single pusher or a set of two pushers are provided at each of the circumferential positions. In the case of the single pusher, since a forward end of the rod of the cylinder unit is coupled to a rear end of the pusher, the overall length becomes very long, so that, in many cases, pushers are respectively disposed on both sides of the cylinder unit and the two pushers are used as a set. In either case, the cylinder units are fixedly disposed outside the heating furnace apparatus, the positions and attitudes of the pushers 63 which are guided by the guide portions 53A in the outer cylinder 53, as well as the rods of the cylinder devices 64, are naturally determined, and therefore cannot be adjusted.
However, the pushers are elongated, so that fabrication errors, deformation during the operation, their inclination due to clearances in the guide portions, and so on are liable to occur. Consequently, the sliding in the guide portions can cease to be smooth, and excessively large loads may be applied to the rods of the cylinder units. In the case where two pushers are made as one set, a load is applied to the rod in such a manner as to bend the rod unless the loads on the respective pushers are equal. Such excessively large loads on the rods become particularly noticeable since thermal deformation occurs when the pushers are subjected to heating as in the heating furnace apparatus, so that a countermeasure thereon has been called for.